Uniden scanners seem to be best at RXing EDACS Narrowband. You can do it with Whistler and/or GRE but Uniden makes it easiest to trunk-track and program EDACS Narrowband systems and groups.
As KG7PBS said however, if you can get a P7100 programmed exactly for the groups you want to monitor, receive only of course, it is a better receiver, both audio wise and build quality.